/Engine/Source/Editor/GameProjectGeneration/Public/GameProjectUtils.h
Check to see if the given path is a valid place to put source code for this project (exists within the source root path)
true if the path is valid, false otherwise
static bool IsValidSourcePath ( const [FString](API\Runtime\Core\Containers\FString) & InPath, const [FModuleContextInfo](API\Runtime\Projects\FModuleContextInfo) & ModuleInfo, [FText](API\Runtime\Core\Internationalization\FText) *const OutFailReason )